Define: science of body structures and their relationships
Define: science of body functions
Name the steps of the scientific method.
Define: use of senses to notice and study a phenomenon
Define: potential testable explanation for a phenomenon, based on observations and prior knowledge and experience
Define: implementation of specific materials and methods designed to test a hypothesis; should include a control group and experimental group(s)
Define: results generated by conducting experimental tests
Define: statements based on analysis of test results that discuss evidence to support or reject the hypothesis
What happens if many related hypotheses are tested repeatedly over time and consistently yield the same results?
It may lead to scientific theory.
Define: widely accepted concepts based on extensive experimental evidence
Define: also based on extensive experimental extensive, but arise from numerous studies that have been shown to produce exactly the same results every time under the same circumstances
Define: condition of equilibrium in the body's internal environment due to the constant interplay of all the body's regulatory processes
Define: sum of all chemical processes that occur in the human body
Define: phase of metabolism that involves breaking down complex chemical substances into simpler ones; = decomposition reactions
Define: phase of metabolism that involves building complex chemical substances from smaller, simpler ones; = synthesis reactions
Define: any abnormality of function
Define: (more specific) illness characterized by a recognizable set of signs and symptoms
Define: subjective changes in body functions and not apparent to observer; examples: headache, nausea
Define: objective changes a clinician can observe and measure; examples: swelling, rash, fever, high blood pressure
Define: substance that cannot be split into a simpler substance by ordinary chemical means
Define: smallest units of matter that retain the properties and characteristics of an element
Define: number of protons in nucleus of an atom of an element
Atomic number (since number of electrons equals the number of protons, atomic number reveals number of electrons)
Define: sum of protons and neutrons in atom
Define: average of all naturally occurring stable isotopes of a given element in AMU (Daltons)
Atomic mass (weight)
Define: atoms of element that have different numbers of neutrons and thus different mass numbers, but have same number of protons and electrons, so same chemical properties
Define: atom that has positive or negative charge due to giving up or gaining electrons (ionization), which results in unequal number of protons and electrons
Define: two or more atoms (same or different) joined together by sharing of electrons
Define: substance that contains two or more different elements
Define: force of attraction that holds ions having opposite charges together
Define: two or more atoms (same or different) share one or more pairs of their valence electrons equally
Nonpolar covalent bond
Define: two or more atoms (same or different) share one or more pairs of their valence electrons unequally and results in partial negative charge near atom with greater electronegativity and partial positive charge near other atoms
Polar covalent bond
Define: occur between polar molecules that contain polar covalent bonds between H and very electronegative atoms, such as O-H, N-H, or F-H bonds
Hydrogen (H) bonds
Define: releases more energy than it absorbs
Define: absorbs more energy than it releases
Define: special type of exchange reaction that involves transfer of electrons between atoms or molecules
Oxidation-reduction (redox) reactions
Define: in general, lack carbon and are structurally simple; include water, many salts, acids, and bases
Define: contain carbon and many are relatively large and have unique characteristics that allow them to carry out complex functions; include carbohydrates, lipids, proteins, nucleic acids, and ATP
Define: major source of energy used to power reactions in body that require energy; most of this in the cell is produced in the mitochondria and produced by aerobic cellular respiration
Adenosine triphosphate (ATP)
Name the 6 major nutrients.
What is the most important and abundant inorganic compound in all living systems?
Define: the storage form of carbohydrates
Define: storage form of lipids
Are proteins stored for future use?
Name the 4 levels of protein structural organization.
Describe the protein structural organization of the primary level.
Has unique aa sequence joined by covalent peptide bonds
Describe the protein structural organization of the secondary level.
Has repeated twisting or folding neighboring amino acids in polypeptide chain (alpha helixes and pleated sheets)
Describe the protein structural organization of the tertiary level.
Has 3-D folding pattern formed by various bonds; determines shape and how a protein will function
Describe the protein structural organization of the quaternary level.
Has an arrangement of two or more polypeptide chains relative to each other
What is the pH scale of 0-14 based on?
Molar concentration of hydrogen ions
What does pH 7 mean?
midpoint; neutral pH; where concentration of hydrogen and hydroxide are equal
What classifies as acidic?
Below pH 7
What classifies as basic (alkaline)?
Above pH 7
Describe an acid.
Below pH 7, proton donor, dissociates into hydrogen and anions
Describe a base.
Above pH 7, proton acceptor, dissociates into cations and hydroxide or another proton acceptor, such as NH3
Describe a salt.
Dissociates into cations and anions, neither of which is hydrogen or hydroxide
Acid + base = ?
Acid + base = Salt + water
Do pH of body fluids differ?
Yes, but each has narrow normal limits, so buffer systems maintain pH balance inside and outside of cell
Define: substance that resists drastic changes in pH (maintains pH) by converting strong acids or bases into weak ones
Define: encloses and protects cell and contains functional proteins such as enzymes that catalyze chemical reactions, receptors that bind ligands and regulate cellular activity, transporters that regulate what enters and exits cell, and cell identity markers
Define: cellular contents between the plasma membrane and the nucleus; includes cytosol and organelles
Define: fluid that surrounds organelles
Define: specialized structures with characteristic shapes and specific functions in cell growth, maintenance, and reproduction
What does organelles include?
Nucleus, nucleoli, ribosomes, rough ER, smooth ER, Golgi apparatus, mitochondria, centrioles, lysosomes, peroxisomes, and other structures
Define: spherical or oval-shaped structure where most of cell's DNA and nucleoli are located; "control center of the cell"
Define: one or more spherical bodies in nucleus that are sites of rRNA synthesis and assembly of rRNA and proteins into ribosomal subunits
Define: site of protein synthesis; attached to nuclear envelope and rough ER, free in cytosol, and in mitochondria
Define: network of folded membranes with attached ribosomes that synthesize proteins, which then enter RER for processing and sorting; synthesizes glycoproteins and phospholipids
Rough endoplasmic reticulum (RER)
Define: network of folded membranes (with no ribosomes) that synthesizes fatty acids and steroids and may have other functions, such as detoxification of harmful substances, depending on cell type
Smooth endoplasmic reticulum (RER)
Define: modifies and packages proteins synthesized in rough ER for transport
Define: generate most of cell's ATP for energy to drive cellular activities; "powerhouse of the cell"
Define: form mitotic spindle during cell division and involved in construction of structures such as flagella and cilia
Define: membrane-enclosed vesicles that contain digestive and hydrolytic enzymes that break down foreign cells, worn out organelles, and a wide variety of molecules
Define: contain oxidative enzymes that can deactivate harmful substances
What is the structural framework of the cell's plasma membrane?
A lipid bilayer: two back to back layers made up of primarily phospholipids plus cholesterol and glycolipids
What is the structural framework of the cell's plasma membrane described as?
A "fluid mosaic model": moving sea of fluid lipids with a mosaic of different functional proteins
Is the cell's plasma membrane selectively permeable?
Yes, it allows free passage of many lipid-soluble molecules but selectively controls crossing of ions or polar substances through transporter proteins
Define: consists of nuclear division during cell division that produces 2 identical daughter cells with diploid number of chromosomes; mainly in somatic cell division
What are the 4 phases of mitosis?
Define: cytoplasmic division during cell division; begins in late anaphase, completed in telophase
Define: period between cell divisions during which cell is functionally and metabolically active and also undergoes growth and duplicates its DNA, organelles, and cytosolic components in anticipation of cell division
Define: reproductive cell division that produces gametes (oocytes in females and sperm in males) in which the number of chromosomes in the nucleus are reduced by half (haploid number)
Define: synthesis of DNA from DNA template
Define: synthesis of mRNA from DNA template
Define: synthesis of amino acid sequence of protein from mRNA template
Define the structure of DNA.
- Double stranded and has double helix structure resembling spiral ladder
- Sides of ladder are formed by alternating deoxyribose sugars and phosphate groups
- Rungs are formed by nitrogenous base pairs joined to each other by hydrogen bonds
Name the 4 nitrogenous bases of DNA.
What does thymine pair with?
What does guanine pair with?
Describe the structure of RNA.
- Differs from DNA
- Single-stranded instead of double-stranded
- Contains ribose instead of deoxyribose
- Contains uracil rather than thymine
What does uracil pair with?
What does guanine pair with?
Cytosine (same as DNA)
Name the 3 kinds of RNA made from DNA template.
1) messenger RNA (mRNA)
2) ribosomal RNA (rRNA)
3) transfer RNA (tRNA)
Describe the function of mRNA.
Directs protein synthesis
Describe the function of rRNA.
Joins with ribosomal proteins to make ribosomes
Describe the function of tRNA.
One end binds specific amino acid and other end has anticodon that base pairs with complimentary codon on mRNA, to hold amino acid in place on ribosome until it is incorporated into protein during translation
Define: each sequence of 3 nucleotides in mRNA that base-pairs with a DNA base triplet
Codon (in mRNA)
Define: nucleotide triplet on tRNA that base pairs with complimentary mRNA codon
Define: regions within gene that do not code for parts of protein
Define: regions within gene that do code for parts of protein
Transport processes that move substances across cell membranes are classified as passive or active depending on....?
Depending on whether they require energy
Define: substances uses its own kinetic energy to move down it concentration or electrochemical gradient across membrane until it reaches equilibrium (equal on both sides); does not require energy
Define: allows passage of nonpolar substances
Simple diffusion through lipid bilayer (passive transport)
Define: allows passage of small polar or charge substances (mainly ions)
Facilitated diffusion through channels (passive transport)
Define: allows passage of larger and highly polar/charged substances via transporter protein
Facilitated transport (diffusion) transporters (passive transport)
Define: energy-requiring process in which transport proteins move solutes across membrane against (up) concentration gradient; requires energy
Define: energy derived from hydrolysis of ATP to "pump" substance across membrane against (up) its concentration gradient
Primary active transport
Define: harnesses potential energy of steep Na+ or H+ concentration gradient (established by primary active transport of these ions) to transport substance up its concentration gradient as Na+ or H+ move down their concentration gradient
Secondary active transport
Define: move two or more substances in same direction (part of secondary active transport)
Define: move two or more substances in opposite directions (part of secondary active transport)
Define: vesicles, small sacs that bud off from an existing membrane, transport substances between structures within cell or in and out of cell
Define: materials move into a cell in a vesicle formed by plasma membrane
Define: membrane enclosed "secretory" vesicles form inside cell, fuse with plasma membrane, and release their contents into extracellular fluid
Define: net movement of water across membrane not permeable to solutes
Define: measure of solution's ability to change volume of cells by altering their water content
Define: concentrations of solutes same on both sides of membrane, so water enters and exits at same rate and cells maintain normal shape and volume
Define: has lower concentration of solutes than cytosol, so water enters cells faster than it leaves causing cells to swell and burst
Define: has higher concentration of solutes than cytosol, so water moves out of cells faster than it moves in causing cells to shrink
Define: contact points between plasma membrane of tissue cells
Define: transmembrane proteins fuse adjacent cells' plasma membranes together to retard the passage of substances and form water tight seal so common in urinary and digestive tracts
Define: cells are joined by cadherin proteins of adjacent cells that insert into protein plaques inside plasma membrane so help epithelial surfaces resist separation
Define: have plaques and cadherins that attach cells to one another, but also have intermediate filaments that extend from desmosomes on one side of cell across cytosol to desmosomes on opposite side of cell to prevent cells from separating under tension so common in epidermis and cardiac muscle
Define: similar to desmosomes but contain integrins, rather than cadherins and anchor cells to basement membrane between epithelium and connective tissue
Define: membrane proteins called connexins form tiny fluid-filled tunnels called connexons that connect neighboring cells and allow rapid communication and diffusion of substances between the cells so common in nervous tissue and cardiac muscle
Name the 4 basic types of body tissues.
1) Epithelial tissue
2) Connective tissue
3) Muscle tissue
4) Nervous tissue
Define: covers body surface, lines hollow organs, body cavities & ducts, and forms glands
Define: protects and supports body and organs
Define: generates physical force needed to make body structures move
Define: detects changes in conditions inside and outside of body and responds by generating nerve impulses that control other tissues help maintain homeostasis
Name 4 examples of exocrine glands.
1) Sudoriferous glands
2) Sebaceous glands
3) Ceruminous glands
4) Goblet glands
Define: exocrine glands that secret sweat into hair follicles or onto the skin's surface to lower body temperature
Define: exocrine glands connected to hair follicles that secrete an oily substance to help prevent hair and skin from drying out
Define: modified sweat glands in external auditory canal that secret ear wax to impede entrance of foreign particles
Define: unicellular exocrine glands that secret mucus to help lubricate and protect lining of GI tract and help trap foreign particles in respiratory tract so they can be moved back out by cilia
Define: includes tissues such as adipose (loose CT), tendons & ligaments (dense CT), cartilage, bone, blood, and lymph
Connective tissue (CT)
Describe connective tissue.
- Binds together, supports, and strengthens other tissues (loose and dense CT)
- Protects and insulates internal organs (adipose)
- Compartmentalizes structures such as skeletal muscles (loose & dense)
- Major transport system (blood)
- Stored energy reserves (adipose fat tissue)
- Main site of immune responses (lymph and white blood cells)
Define: muscle fibers use ATP to generate force
Name the 3 types of muscle tissue.
Define: usually attached to bones of skeleton, voluntary, and striated (alternating light/dark bands on stained fibers)
Define: forms most of wall of heart, involuntary, branched, striated, and contains intercalated discs (with gap junctions and desmosomes)
Define: located in walls of hollow organs (blood vessels, airways, digestive, urinary, reproductive), involuntary, and nonstriated
Define: controls and integrates all body activities within limits that maintain life
Name the 3 basic functions of nervous tissue.
1) Sensing internal and external changes with sensory receptors
2) Processing, interpreting, and remembering those changes
3) Responding to those changes with effectors (muscles and glands)
Define: functional unit of nervous system; has the capacity to produce action potentials; receive and conduct nerve impulses
Define: nervous system cells that have supportive roles; do not receive or conduct nerve impulses
Define: includes skin, hair, and nails
Define: covers body, protects underlying tissues, and contains accessory structures that function in protection from microbes and sun, thermoregulation, and tactile sensations
Define: exocrine glands found throughout most of the body that secrete sweat into hair follicles or onto the skin's surface to lower body temperature
Eccrine suderiferous (sweat) glands
Define: exocrine glands connected to hair follicles that secrete an oily substance to help prevent hair and skin from drying out
Sebaceous (oil) glands
Define: smooth muscle near hair that is stimulated by autonomic nervous system to contract under conditions of stress (such as cold or fright)
Arrector pili muscle
Define: encapsulated nerve ending that senses light touch
Define: encapsulated nerve ending that detects deep pressure
Name the 3 functions of the skeletal system.
Define: structural framework for body; supports soft tissues and provides attachment points for tendons of most skeletal muscles
Define: protects many internal organs from injury
Define: bones and muscles work together to produce movement; muscles are attached to bones, so when they contract, they pull bones
Name the 3 functions of bone tissue.
1) Mineral homeostasis
2) Blood cell production (hemopoieis or hematopoieis)
3) Triglyceride storage
Define: several minerals, mainly calcium and phosphorus, are stored in bone tissue and released on demand into blood to maintain critical mineral balances and to distribute minerals to other parts of body
Describe blood cell production.
- Function of red bone marrow (in spongy bone)
- Occurs in skull, ribs, sternum, vertebrae, pelvis, and ends of arm and thigh bones
- Produces red blood cells, white blood cells, and platelets
Describe triglyceride storage.
- Function of yellow bone marrow
- Consists mainly of adipocytes, which store triglycerides
- Serves as important energy reserve (triglycerides)
Define: decrease in angle
Define: increase in angle, usually restoring to anatomical position
Define: movement of a bone away from the midline
Define: movement of a bone towards the midline
Define: movement at distal end of body part in a circle (continuous sequence of flexion, abduction, extension, and adduction)
Define: bone revolves arounds its own longitudinal axis
Define: movement of forearm to turn palm anteriorly or superiorly
Define: movement of forearm to turn palm posteriorly or inferiorly
Define: basic functional units of a myofibril in muscle, separated by z discs
Name the 3 types of proteins that myofibrils are composed of.
1) Contractile proteins
2) Regulatory proteins
3) Structural proteins
Name the 2 contractile proteins.
1) Actin (found in thin filaments)
2) Myosin (found in thick filaments)
Name the 2 regulatory proteins.
* Both in thin filaments
Name the 3 structural proteins.
2) M line
What is muscle action stimulated by?
Acetylcholine released from motor neuron at neuromuscular junction that binds receptors on muscle cell membrane and leads to depolarization of membrane to threshold potential via opening of Na+ channels
What is resting membrane potential?
What is threshold potential?
Define: involves opening of Na+ ion channels and produces action potential if threshold is reached, which causes opening of more Na+ channels and leads to contraction due to opening of voltage-gated Ca++ channels
Depolarization (potential becomes more positive, moves towards threshold potential)
Define: involves closing of Na+ channels and opening of K+ channels and leads to relaxation due to closing of Ca++ channels
Repolarization (becomes more negative, restores resting potential)
Define: heads of myosin bind and form crossbridges with actin and pull the thin filaments toward the M line (midline); requires energy from ATP hydrolysis
Sliding filament mechanism of skeletal muscle contraction
In relaxed muscle (no Ca present), ____________, held in place by ____________, covers myosin binding sites on actin and prevents the formation of crossbridges
When sufficient Ca is present, it binds to ____________, which changes shape and moves ___________, thereby exposing binding sites to allow crossbridge formation
What is resting membrane potential in a neuron?
What is resting membrane potential in a muscle cell?
Define: small local changes from resting membrane potential
Define: membrane becomes more positive; can build to threshold potential, so excitatory
Define: membrane becomes more negative; makes it less likely to reach threshold, so inhibitory
What is threshold potential?
-55 mV; depolarizing potential required to generate an action potential
Name the 2 divisions of the nervous system.
1) Central Nervous System (CNS)
2) Peripheral Nervous System (PNS)
Define: consists of brain and spinal cord
Central Nervous System
Define: consists of the cranial nerves and spinal nerves, which contain both sensory and motor fibers
Peripheral Nervous System
Name the 3 divisions of the PNS.
1) Somatic (voluntary) nervous system (SNS)
2) Autonomic (involunary) nervous systems (ANS)
3) Enteric nervous system (ENS)
Define: sensory neurons from skin and special sensory receptors to the CNS motor neurons to skeletal muscle
Somatic nervous system
Define: sensory neurons from visceral organs to CNS; motor neurons to cardiac muscle, smooth muscle, and glands; sympathetic division: "fight or flight" stress and emergency responses; parasympathetic division: "rest and digest" maintenance of homeostasis (usually dominates)
Autonomic nervous system
Define: involuntary sensory and motor neurons that control gastrointestinal tract
Enteric nervous system
Define: functional unit of nervous system
Describe a neuron.
- Conducts (sends and receives) nerve impulses to communicate with and control actions of other cells
- Has 2 types of processes: dendrite(s) and one axon
Define: one to many short, branched processes that receive input and conduct graded potentials toward cell body
Define: one thin, typically long process that conducts nerve impulses away from cell body (sends output) and releases neurotransmitter from synaptic end bulbs at ends of axon terminals; only one present, but branches to make many contacts; most are myelinated
Define: nervous system cells that have supportive roles; do not conduct nerve impulses
Name the 4 neuroglia found in the CNS.
4) Ependymal cells
Define: maintain chemical environment in CNS and help form the blood-brain barrier
Define: phagocytic role
Define: form myelin sheath around CNS axons
Define: line the cerebral cavities and produce cerebrospinal (CSF) fluid
Name the 2 neuroglia found in the PNS.
1) Schwann cells
2) Satellite cells
Define: form a myelin sheath around PNS axons
Define: role not clear, but believed to maintain chemical environment in PNS
Most axons of PNS neurons are covered by what?
Myelin sheaths produced by Schwann cells
Define: gaps between myelin sheaths where many voltage-gated channels are located
Nodes of Ranvier
Define: myelin acts as electrical insulator and speeds conduction of nerve impulses
Define: slow because small diameter and no myelin insulation
Define: rapid nerve conduction that occurs in myelinated fibers where signal jumps node to node of Ranvier
Define: slow nerve conduction that occurs in unmyelinated fibers where entire length of axon must be depolarized step by step
Define: released from axon terminals, diffuse across synaptic cleft, and bind to receptors on target cell; may be excitatory or inhibitory
Define: excitatory on neuromuscular junction but inhibitory at others
Define: major excitatory neurotransmitter in CNS and PNS
Define: major inhibitory neurotransmitter in forebrain
Define: major inhibitory neurotransmitter in brain stem, spinal cord, and PNS
Define: regulates mood, dreaming, and awakening from sleep
Define: regulates skeletal muscle tone
Define: regulates mood, temperature, and induction of sleep
Define: enhances perception of pain
Define: relieve pain by blocking the release of substance P
Define: pathways for travel of sensory and motor information
Spinal cord nerve tracts
Name the 2 spinal cord nerve tracts.
1) Ascending nerve tracts
2) Descending nerve tracts
Define: carry sensory information from spinal cord to brain
Ascending nerve tracts
Define: carry motor information from brain to spinal cord
Descending nerve tracts
Define: extends from brain stem to cerebrum and surrounds third ventricle
Define: relays almost all sensory input to the cerebral cortex
Define: controls and integrates activities of the autonomic nervous system and the pituitary gland
Define: contains pineal gland, which secretes melatonin to promote sleepiness
Subthalamus containing subthalamic nuclei that work with basal ganglia to help control body movements
Define: portion of brain between spinal cord and diencephalon
Name the 3 parts that make up the brain stem.
1) Medulla oblongata
Describe the medulla oblongata.
- Lower part of the brain stem
- Relays motor and sensory impulses between other parts of the brain and spinal cord
- Has a cardiovascular center that regulates the force and rate of heartbeat and diameter of blood vessels
- Has a respiratory center that adjusts the rhythm of breathing
- Middle part of the brain stem
- Relays impulses from one side of the cerebellum to other and between medulla and midbrain
- Has pneumotaxic and apneustic area to help control breathing
- Upper part of the brain stem
- Relays motor impulses from cerebral cortex to pons and secretory impulses from spinal cord to thalamus
- Includes the red nuclei, which function with the cerebellum to coordinate muscular movements
- Includes substantia nigra that releases dopamine for regulating muscle tone
Define: posterior to medulla and pons and inferior to posterior cerebrum
List the functions of the cerebellum.
- Coordinate complex, skilled movements
- Regulate posture and balance
- May have role in cognition and language processing
Define: consists of cerebral cortex (outer rim of gray matter), white matter (interior), and gray matter nuclei deep within white matter
The cerebrum is divided into...?
Left and right hemispheres
What is the function of each hemisphere?
Receives sensory input from and controls muscles on opposite sides of body
Define: functional asymmetry between the two hemispheres
What is the left hemisphere important for?
Reasoning, numeric, and scientific skills, language
What is the right hemisphere important for?
More specialized for art and music, spacial and pattern perception, emotional content of language, and face recognition
Name the 5 lobes of the brain.
Define: receive nerve impulses for specific stimuli; determines location and basic characteristics of stimuli
Primary sensory areas
Define: controls voluntary contractions of specific muscles or muscle groups
Primary motor area
Define: brain region where planning and production of speech occurs
Broca's speech area
Define: inability to use or comprehend words; caused by injury to language areas (Broca's speech area)
Define: usually receive input from primary sensory areas and other brain regions, including thalamus; integrate/interpret sensory info by comparing with past sensory (memory)
Sensory association (secondary sensory) areas
Define: motor association area that controls learned skilled movements and stores memory for such movements
Define: 3 nuclei deep within each cerebral hemisphere that help regulate initiation and termination of movements
Define: has primary role in emotions, olfaction, and memory
Define: involved in stimulating and maintaining arousal and consciousness
Reticular activating system (RAS)
Define: acquiring new knowledge
Define: process of retaining and retrieving information
Define: collection of action potentials and graded potentials generated by neurons in brain
Define: record of brain waves (electrical signals) used for studying normal brain activity and diagnosing disorders such as tumor, trauma, and epilepsy
Define: state of altered or partial consciousness from which a person can be aroused
Name the 2 components of sleep.
1) Non-rapid eye movement (NREM)
2) Rapid eye movement (REM)
Do both alternate throughout sleep?
When do most dreams occur?
During REM sleep
What does sleep deprivation impair?
Attention, learning, and performance
Name the 4 receptors for somatic sensations.
4) Tactile receptors
Define: sense joint position and movement and muscle length and tension
Define: sense pain; found in all tissues of the body except the brain
Define: sense warmth or cold
Define: sense touch, pressure, vibration, tickle, and itch
What do special senses involve?
Olfaction, gestation, vision, hearing, and equilibrium; involve much more complex, specialized receptors that somatic sensations
Define: sense of taste; chemical sense in which tastants are dissolves in saliva and detected by gustatory hairs in taste buds
Define: detect 5 gustatory stimuli
Name the 5 gustatory stimuli.
Where does the taste on the anterior 2/3 of the tongue come from?
Sensory axons of the facial nerve
Where does the taste on the posterior 1/3 of the tongue come from?
Sensory axons of the glossopharyngeal nerve
Define: sense of smell; chemical sense in which odorants are dissolved and detected by olfactory hairs of olfactory receptors
Define: formed by bundles of olfactory receptor (1st order neurons) axons that terminate in olfactory bulb
Olfactory nerve (cranial nerve I)
Define: formed by axons of olfactory bulb neurons (2nd order neurons) that project to lateral olfactory area in temporal lobe
Define: transparent and curved coat that covers iris that functions in refraction of light; helps focus light onto retina
Define: refracts light; help focus light on macula lutea of retina to provide clear images
Define: colored portion of eye that faces anteriorly
Define: hole in center that functions to regulate amount of light entering eye
What is changing size of pupil regulated by?
Define: circular muscles contract in bright light to constrict pupil
Define: radial muscles contract in dim light to dilate pupil
Define: serves as beginning of visual pathway
Define: site where optic nerve exits back of eyeball; blind spot because contains no photoreceptors (rods and cones)
What are the 2 layers of the retina?
Define: nonvisual portion that has melanin; absorbs stray light and help keep image sharp and clear
Define: multilayered outgrowth of brain that processes visual input; then sends nerve impulses down axons that form optic nerves
Where are photoreceptors located?
What are photoreceptors named for?
The shape of their outer segment
Define: photoreceptors active in dim light that detect shades of gray; contains photopigment called rhodopsin
Define: photoreceptors active in bright light with photopigments to detect color; each one contains one of 3 different photopigments (opsins) for color; produce sharper vision than rods
Define: normal eye that can sufficiently refract light rays from an object 20 ft away so that a clear image is focused on the retina
Why does nearsightedness occur?
Occurs because eyeball is too long relative to focusing power of cornea and lens
Why does farsightedness occur?
Occurs because eyeball is too short relative to focusing power of cornea and lens
Define: parts of image are out of focus, producing blurred or distorted vision
Why does astigmatism occur?
Occurs due to irregular curvature of cornea
Name the 3 major processes involved in image formation.
1) Refraction (bending of light) by cornea and lens to focus light rays onto retina
2) Accommodation of lens: increasing curvature of lens so light is still focused as objects move closer to eye
3) Constriction of pupil to prevent light rays from entering through periphery of lens which minimizes blurriness
Define: collects sound waves
Define: directs sound waves to tympanic membrane
External auditory canal (meatus)
Define: vibrated by sound waves, which vibrates ear ossicles in turn
Tympanic membrane (eardrum)
Define: transmit and amplify vibrations to oval window; include: malleus, incus, and stapes
Auditory (ear) ossicles
Define: contains series of fluids, channels, and membranes that transmit vibrations to organ of Corti for hearing
Define: contains hair receptors cells that produce receptor potentials, which elicit nerve impulses in cochlear branch of vestibulocochlear nerve (cranial nerve VIII)
Organ of Corti
Where do nerve impulses eventually reach?
Primary and secondary auditory areas involved in awareness and interpretation of sound
Define: contains receptor organs for sense of equilibrium
What does the vestibular apparatus include?
- Semicircular ducts
What does movement of stereocilia on hair cells of saccule and utricle lead to?
Generation of nerve impulses in vestibular brach of vestibulocochlear nerve (cranial nerve VIII)
Define: maintenance of body position (mainly the head) relative to the force of gravity
Define: maintenance of body position (mainly the head) during sudden movements such as rotation, acceleration, or deceleration
Define: contain hair (receptor) cells for dynamic equilibrium
Define: contain hair cells for dynamic and static equilibrium
Utricle and saccule